An apparatus that irradiates surrounding objects with a light beam such as a laser beam and receives the reflected beam to collect information on the surrounding objects is known (US 2014/0211194A1). In such an apparatus, a light-receiving element that transforms the received light beam into an electric signal must be installed on a rotating portion. When the light-receiving element is installed on the rotating portion, the rotating portion is required to be upsized, and therefore the whole apparatus is upsized. Further, a device for transmitting the electric signal or the output of light-receiving element from the rotating portion to the outside is required so that the apparatus becomes complicated in configuration.
A light-receiving optical system for realizing a compact and simply configured apparatus that irradiates surrounding objects with a light beam such as a laser beam and receives the reflected beam to collect information on the surrounding objects has not been developed.
Patent document: US 2014/0211194A1
Accordingly, there is a need for a light-receiving optical system for realizing a compact and simply configured apparatus that irradiates surrounding objects with a light beam such as a laser beam and receives the reflected beam to collect information on the surrounding objects. The problem to be solved by the present invention is to provide a light-receiving optical system for realizing such a compact and simply configured apparatus as described above.